Primer pairs were designed to amplify the genomic DNA of alpha-farnesene synthase gene （AFS） by PCR, the PCR products were sequenced, the sequences were spliced and compared to eDNA （accession No. AY182241 ） in the GenBank, then the genomic sequence and intron-exon organization of AFS gene were obtained. The AFS genomic sequence has been registered in GenBank （accession No. DQ901739）, it had 6 introns and 7 exons, encoded a protein with 576 amino acids. The sizes of 6 introns were 108 bp, 113 bp, 〉1 1300 bp, 125 bp, 220 bp and 88 bp, and their phase were 0, 1, 2, 2, 0, 0, respectively. The sizes of deduced amino acids of 7 exons were 57, 89, 127, 73, 48, 83 and 99, respectively. The AFS protein contained three motifs, the RR （ X8 ） W motif was encoded by a sequence in exon 1, the RxR motif and DDxxD motif were encoded by two sequences in exon 4. The AFS genomic sequence （ accession No. DQ901739） was compared to eDNA （ accession No. AY523409） in the GenBank, it was found that there were 6 single-nucleotide polymorphisms between the two sequences, four of which caused mutations at the amino acid level. Interestingly, one amino acid mutation （291R→G） was found in RxR motif, it deserves further investigation whether the alpha-farnesene synthesis ability and superficial scald susceptibility of apples were influenced by this amino acid mutation and other mutations.
Acta Horticulturae Sinica
E-mail： yuankj@vip. sina. com